Several subject matter experts, including John Gruber and Engadget, confirm the authenticity of the model shown in photos. However, they remain cautious about the fact that this model, the final design, although the front and back seem to be the right one, the edge could be different!
The material on the back would be designed in a kind of ceramic, which suggests that the aluminum of the iPhone V1 and the plastic of the 3G and 3Gs model will no longer be used.
We discuss it on the forum
The idea of a ceramic shell is not new, in 2006 a patent in this sense had already been filed by Cupertino. The advantage of a ceramic shell, in addition to the absence of microcracks, is that it allows radio waves to pass through perfectly. On iPad 3G there is a large black plastic strip to compensate for the aluminum shell.
Finally, according to MacRumors, the battery is removable. A small hole was seen on the top and suggests that this should allow the rear part to be destroyed.